The road sets off in the N-I from Andoain, south of San Sebastián. It heads south east by the Aralar Range crossing the green mountainous region of north-eastern Navarre past the stream Larraun until Irurtzun, where a more rolling and drier landscape starts (junction with the N-240). The A-15 passes south of Pamplona with junctions with the N-111 and N-121 as well as N-135.
The A-15 heads south over the Puerto del Carrascal (594m) and past Tarana and into the Rio Aragón valley. The road ends at Autopista AP-68.